Monjurosuchus
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Monjurosuchus Temporal range: Early Cretaceous |
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| Monjurosuchus splendens fossil in the Beijing Museum of Natural History | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | †Choristodera |
| Family: | †Monjurosuchidae |
| Genus: |
†Monjurosuchus Endo, 1940 |
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Monjurosuchus is a genus of choristoderan reptile that lived in what is now China and Japan during the Early Cretaceous. It has large eyes, a rounded skull, robust legs with short claws, and a long, thin tail. Fossils have been found that preserve soft tissue, showing that it had soft skin and webbed feet. Monjurosuchus has been placed in the family Monjurosuchidae along with Philydrosaurus, but the relationships of early choristoderes remains unclear.
Monjurosuchus was first found in China as part of the Early Cretaceous Jehol Biota. Named in 1940, the type species M. splendens was the first reptile described from the Yixian Formation. The holotype specimen was lost during World War II but was replaced in 2000 by a recently discovered neotype preserving soft tissue. In 2007, remains were described from the Okurodani Formation of the Tetori Group of Japan. The Japanese material represents a different species of Monjurosuchus that has not yet been named.
Monjurosuchus was a small choristodere, reaching a length of 40 cm with a 5 cm skull. Unlike related choristoderes, Monjurosuchus has a relatively short neck with eight vertebrae, one less than usual. The skull is rounded rather than pointed and is dorsoventrally flattened in all fossils. The eye sockets are large and prominent temporal regions extend from the back of the skull. The jaws are lined with small, sharp teeth, while the palate is covered in closely spaced tooth batteries. One distinguishing feature of Monjurosuchus is the lack of a lower temporal fenestra, a hole in the back of the skull that is common in many other diapsid reptiles, including most choristoderes. Monjurosuchus is also distinct in having small spikes on the edge of the squamosal bone at the back of the skull.
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